Fig. 4
From: Degradation and inactivation of Shiga toxins by nitrogen gas plasma
Decreasing cell toxicity of Stx1 and Stx2 after nitrogen gas plasma treatment. A coverslip containing dried spots from 20 μl aliquots of a 1 μg/ml solution of Stx1 (a) and Stx2 (b) was treated with nitrogen gas plasma using BLP-TES device (1.5 kpps) for 0, 1, 2, 5, 15, and 30 min. The recovered samples were diluted 50-fold with minimum essential medium (MEM) and then added to HEp-2 cells at 100 μl/well in a microtiter plate. After incubation at 37 °C for 24 h for Stx1 and for 48 h for Stx2, the viability of HEp-2 cells was monitored using a Cell counting kit 8 (Dojindo, Kumamoto, Japan). The activity of Stx, which was measured on the basis of cell toxicity of Stx to HEp-2 cells, was significantly inhibited, as compared with no treatment (0 min), by 30 min of nitrogen gas plasma treatment using BLP-TES (*p < 0.05, **p < 0.01)